Michael E. Mann is a physicist and climate scientist who has conducted research related to global climate change, including reconstruction of climate data from the past millennium and modeling long-term behavior of the climate system. He is the creator of the familiar "hockey stick" graph showing the recent, rapid upturn in the earth's temperature. He is also the director of the Earth System Science Center at Pennsylvania State University, the principle author of Encyclopedia Britannica's entries on climate change, and a frequent face on TV newscasts when reporters need a scientist to explain the science in layman's terms.

In the so-called "Climategate scandal" of late 2009, emails from Mann were among the communications hacked from a server used by the Climatic Research Unit at the University of East Anglia. Skeptics of climate change used the emails to impugn Mann, other scientists, and the general concept of man-made climate change, but several investigations found no evidence of data falsification by Mann or any of the other scientists who authored the purloined emails. In his 2012 book The Hockey Stick and the Climate Wars, Mann warns that "public discourse has been polluted now for decades by corporate-funded disinformation — not just with climate change but with a host of health, environmental and societal threats."